This invention relates generally to the collection of blood samples and more specifically to a method and an assembly for collecting fluid samples with a retractable needle and fluid collecting tube holding device which following the stroke of the plunger, automatically retracts the needle into the body of the assembly.
Blood samples and other medical specimens are routinely taken and collected in a specimen collection container. The typical blood collection container is a hollow blood collection tube with one end closed by a semi-spherical portion and the other end open. The open end is sealable by an impervious elastomeric cover.
To collect a blood sample, the tube is used in concert with a tube holding device. Normally the holding device has a hollow needle extending through the closed end of a tubular housing. The tubular housing has an opposed open end for accepting the blood collection tube. The hollow needle is inserted through the dermal layer into the lumen of the blood vessel into the circulation system of a subject to direct blood there through towards the interior compartment of the holding device. The collection container is inserted through the open end of the holder so that the hollow needle punctures through the elastomeric cover of the collection container. The interior of the collection container is now in direct communication with the circulation system and, having typically been formed in a vacuum, draws blood through the hollow needle and into the collection container. Once enough blood has been drawn, the container may be removed from the holder.
The tube holding device with its contaminated needle presents the danger of an accidental needle stick. Even trace amounts of body fluids from a person with Hepatitis, Acquired Immune Deficiency Syndrome (AIDS) etc. transferred into another""s blood stream can transmit these diseases. Thus, what is needed in the art is a fluid collecting tube holding device that protects from inadvertent needle sticks.
Thus, an object of the instant invention is to provide a fluid collecting tube holder that causes the contaminated hypodermic syringe to retract into the holder, by insertion of a plunger, so that the needle is enclosed within the holder.
It is a further object of the instant invention to provide a plunger device that is either unattached or attached to the fluid colleting tube device holder such that it does not interfere with the collection of the fluid sample but is easily accessible for insertion into the tube holding device.
Another object of the instant invention is to provide a collet which expands and releases a spring biased needle retractor in response to the forward movement of the plunger. The forward end of the outer barrel carries a wedge which insures the collet fingers will spread apart upon forward movement of the collet.
It is yet another object of the instant invention to provide a vent in the plunger. The vent allows air to escape from the interior of the plunger as the needle assembly is retracted by or in response to spring action.
It is still another object of the instant invention is to provide an inexpensive, easily manufactured and used tube holding device with a retractable needle mechanism for safe disposal and prevention of diseases.
It is further objective of the instant invention to provide a method for collecting fluid samples that significantly reduces accidental needle sticks.
Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate objects and features thereof.